Eight times the sum of 9 and some number is 192.

15

Step-by-step explanation:

To solve this, divide 192 by 8:

192/9 = 24

Subtract 9 from 24:

24 - 9 = 15

Therefore, 8 times the sum of 9 and 15 is 192

8 times (9+x) = 192 where x = "that" certain number.

Multiplying the left side through by 8 gives

72+8x=192

8x = 192-72

8x = 120

Since were finding 8, 8 divides the 120 giving 15

Hence, x (that certain number) = 15.